1. Field of the Invention
The invention relates to earth dams, especially, but not exclusively, dams constructed without concrete core walls, and to structurally similar dams such as gob pile dams and those formed of silt. The invention is also applicable to structurally analogous water retaining embankments such as major river levees and sea dikes. p 2. Prior Art
The closest patent art known to applicant consists of the following United States patents:
______________________________________ U.S. Pat. No. Name ______________________________________ 2,138,366 Baird 3,067,585 Hait 3,113,435 Yount 3,234,741 Ionides 3,383,863 Berry 3,415,022 Schaefer -3,568,453 Ziegenmeyer 3,854,292 Nienstadt ______________________________________
Applicant is also aware of the following unpatented prior art in the form of printed publications:
"Water & Sewage Works", March, 1976 - Article entitled "Floating Covers Protect Reservoirs", and Brochures entitled "Pond Liners and Covers of Du Pont Hypalon" and "For Pollution Control-The Unique Du Pont 3110-Pond/Pit Liner System", both brochures published by E. I. du Pont de Nemours & Co. of Wilmington, Delaware.
These references, patented, and unpatented, pertain mainly to relatively quiescent bodies of water such as water reservoirs, settling ponds and impounding basins. Even when related to moving water, as in irrigation or drainage canals and ditches, the objective is containment in the sense of minimizing leakage or seepage, rather than resistance to hydraulic erosion and breach of the impounding structure. The references teach the use of inner linings as distinguished from the outer coverings of the present invention.